Total Synthesis of (+)-Haperforin G.

(+)-Haperforin G was synthesized in 20 steps from commercially available starting materials. A Co-catalyzed intramolecular Pauson-Khand reaction was used for stereoselective construction of cyclopentanone bearing an all-carbon quaternary stereogenic center at the bridge-head position. Light-initiated photocatalysis was used for convergent and asymmetric cross-coupling of the unstabilized C(sp 3 ) radical with an enone. The developed chemistry paves the way to the synthesis of structurally diverse analogs of haperforin G ( 6 ).